Dynamic Modeling And Characteristic Analysis Of Mine Friction Hoisting System

With the development of economy and society,mine hoist is developing in the direction of high speed,heavy load and large haul.As the key bearing parts of mine hoist,the steel wire rope is easily affected by the external excitation and the sudden change of system motion state to produce violent vibration in high speed motion.With the continuous increase of mine depth,the length of the steel wire rope is different in different positions of the hoisting vessel,which leads to the more complex dynamic characteristics of the hoisting system under the action of external excitation and motion impact.However,there are vibration phenomena in the longitudinal,transverse and lateral directions of the wire rope in the actual operation process.Due to the elastic deformation,the vibration in different directions is coupled with each other,which brings a challenge to the comprehensive analysis of its dynamic characteristics.In order to avoid the abnormal vibration of the wire rope and the fluctuation of dynamic tension aggravating the fatigue and wear of the wire rope,and even causing the rope breaking accident,the vibration mechanism and dynamic tension characteristics of the wire rope in the operation of the lifting system should be defined,and the corresponding vibration control scheme should be proposed accordingly.In order to solve the above problems,the longitudinal-transversal-lateral nonlinear coupling vibration model of the friction lifting system under external excitation is established based on Hamilton principle.The Galerkin method is used to discretize the governing equations of vibration and solve them numerically.The complex dynamics of wire rope under external excitation and motion self-excitation is studied.In order to verify the reliability and effectiveness of the theoretical model,an experiment was designed to test the vibration response of the end of the wire rope during the operation of the mine hoist.The results show that the coupling vibration of the lifting system is mainly longitudinal vibration.Under the influence of external excitation,the lateral and lateral vibration of the wire rope will become more intense with the increase of system speed.When the length of the wire rope increases,the system is more sensitive to the impact caused by the sudden change of motion state,and it is easier to stimulate the intense longitudinal vibration,and the damping attenuation rate is slower.Under the lifting condition,the part near the drum of the wire rope bears greater dynamic tension as the dangerous section of the wire rope,while under the lowering condition,the vibration of the wire rope is more intense and the peak value of dynamic tension is larger when the end of the wire rope reaches the bottom of the well.In view of the impact and vibration phenomenon of the steel wire rope under the sudden change of motion state during the research process,the influence of operating parameters and motion track on the longitudinal vibration and dynamic tension of the steel wire rope was studied.It was found that enhancing the smoothness of motion track could effectively reduce the motion impact on the premise of ensuring the operation efficiency of the system.Therefore,a trajectory optimization method based on the standard logic function is proposed,which can plan a smoother motion curve while using fewer trajectory segments,and effectively suppress the impact vibration and dynamic tension fluctuation caused by the sudden change of motion state.Considering that the length of tail rope increases due to the increase of well depth,the influence on the system cannot be ignored.The vibration law of tail rope and the influence of lifting load,height and longitudinal excitation amplitude of friction wheel on the longitudinal vibration of the system were studied.The results show that the coupling of the boundary between hoisting rope and tail rope will influence each other's vibration,and the longitudinal vibration displacement characteristics of both are similar.The length of hoisting rope and tail rope is the key factor affecting the vibration of the wire rope.When the length of the wire rope is longer,it is more likely to be affected by the impact,resulting in the vibration aggravation.The increase of lifting load,height and longitudinal excitation amplitude will cause more severe longitudinal vibration during the system operation.This study provides analytical thinking and theoretical basis for the related research of mine hoist system,and provides theoretical and technical support for the subsequent engineering design,parameter optimization and vibration control of hoisting machine.